Generally, use of smart devices including touch panels, such as portable terminals, smartphones, or tablets, is increasing. Smart devices are produced in various types ranging from smartphones which have relatively small touch panels to tablets which have large touch panels.
Recently, interest in curved touch panels, so-called three dimensional touch panels, have been heightening. The curved touch panel can increase an actual touch area of the panel as well as the aesthetic thereof.
Meanwhile, in order to produce the curved touch panel, a glass used for a cover glass on the touch panel should be formed in a curved surface.
A method which forms a curved glass by grinding a glass surface using a grinder or the like has been widely used as the method of forming the curved glass. However, the grinding method requires hard work to meet surface roughness and transmittance requirements of the glass, has a high rate of scratching and breakage of the glass, and long forming time is necessary due to high resistance during grinding, and thus there is a problem in that the productivity thereof can be decreased.